The Greenland Ice Sheet holds enough water to raise the world’s sea level by over 7 meters (23 feet). Rising atmosphere and ocean temperatures have led to an ice loss equivalent to over a centimeter increase in global mean sea-level between 1991 and 2015. Large outlet glaciers, rivers of ice moving to the sea, drain the ice from the interior of Greenland and cause the outer margins of the ice sheet to recede. Improvements in measuring the ice thickness in ice sheets is enabling better simulation of the flow in outlet glaciers, which is key to predicting the retreat of ice sheets into the future.

Recently, a simulation of the effects of outlet glacier flow on ice sheet thickness coupled with improved data and comprehensive climate modeling for differing future climate scenarios has been used to estimate Greenland’s contribution to sea-level over the next millennium. Greenland could contribute 5–34 cm (2-13 inches) to sea-level by 2100 and 11–162 cm (4-64 inches) by 2200, with outlet glaciers contributing 19–40 % of the total mass loss. The analysis shows that uncertainties in projecting mass loss are dominated by uncertainties in climate scenarios and surface processes, followed by ice dynamics. Uncertainties in ocean conditions play a minor role, particularly in the long term. Greenland will very likely become ice-free within a millennium without significant reductions in greenhouse gas emissions.

Three visualizations of the evolution of the Greenland Ice Sheet between 2008 and 2300 based on three different climate scenarios are shown below. Each scenario is described briefly in the caption under each visualization. Each of the three visualizations are provided with a date and colorbar as well as without. The regions shown in a violet color are exposed areas of the Greenland bed that were covered by the ice sheet in 2008.

The data sets used for these animations are the control (“CTRL”) simulations and were produced with the open-source Parallel Ice Sheet Model (www.pism-docs.org). All data sets for this study are publicly available at https://arcticdata.io (doi:10.18739/A2Z60C21V).

Above is a visualization of the Greenland Ice Sheet from 2008 to 2300 based on the Representative Concentration Pathway (RCP) 2.6 climate scenario. This is the best case scenario for limiting greenhouse gasses and assumes that emissions will peak by mid-century and decline thereafter.This video is also available on our YouTube channel.

Above is a visualization of the Greenland Ice Sheet from 2008 to 2300 based on the RCP 4.5 climate scenario. This mid-range scenario is based on the assumption that emissions will stabilize by the year 2100 and that forest lands will expand.This video is also available on our YouTube channel.